The DPT is a national, multi-center, NIH sponsored project with the following goals. 1) To identify first and second degree relatives of subjects with IDDM who are at high (>=50%) or intermediate (25-49%) risk of developing IDDM over the next 5 years. 2) To test whether parenteral (high risk) or oral (intermediate risk) insulin will prevent or inhibit the development of IDDM. Children's Hospital Medical Center (CHMC) has participated in the DPT as an Affiliate Center of the Barbara Davis Center for Childhood Diabetes in Denver since 1994. CHMC was named as a Regional Center in October 1997 in order to increase awareness and recruitment in a geographic area.